xfs: refactor xfs_trans_reserve() interface

With the new xfs_trans_res structure has been introduced, the log
reservation size, log count as well as log flags are pre-initialized
at mount time.  So it's time to refine xfs_trans_reserve() interface
to be more neat.

Also, introduce a new helper M_RES() to return a pointer to the
mp->m_resv structure to simplify the input.

Signed-off-by: Jie Liu <jeff.liu@oracle.com>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

diff --git a/fs/xfs/xfs_qm.c b/fs/xfs/xfs_qm.c
index 35a6f56..479c933 100644
--- a/fs/xfs/xfs_qm.c
+++ b/fs/xfs/xfs_qm.c
@@ -865,11 +865,9 @@
 	}
 
 	tp = xfs_trans_alloc(mp, XFS_TRANS_QM_QINOCREATE);
-	if ((error = xfs_trans_reserve(tp,
-				      XFS_QM_QINOCREATE_SPACE_RES(mp),
-				      XFS_CREATE_LOG_RES(mp), 0,
-				      XFS_TRANS_PERM_LOG_RES,
-				      XFS_CREATE_LOG_COUNT))) {
+	error = xfs_trans_reserve(tp, &M_RES(mp)->tr_create,
+				  XFS_QM_QINOCREATE_SPACE_RES(mp), 0);
+	if (error) {
 		xfs_trans_cancel(tp, 0);
 		return error;
 	}
@@ -1740,8 +1738,7 @@
 	int		error;
 
 	tp = xfs_trans_alloc(mp, XFS_TRANS_QM_SBCHANGE);
-	error = xfs_trans_reserve(tp, 0, XFS_QM_SBCHANGE_LOG_RES(mp),
-				  0, 0, XFS_DEFAULT_LOG_COUNT);
+	error = xfs_trans_reserve(tp, &M_RES(mp)->tr_qm_sbchange, 0, 0);
 	if (error) {
 		xfs_trans_cancel(tp, 0);
 		return error;